Seminar Announcement: Osman Sayginer
Data pubblicazione: 12-apr-2021
Tuesday, 13 April 2021, 11:00-12:00
on site: at Sala Stringa - FBK (up to 20 people)
on line: meet.google.com/xqo-jjzu-djg
"Development of Optoacoustic Sensors for Structural Health Monitoring Applications"
IFN-CNR-FBK and DICAM UniTN
Via alla Cascata 56/C,
38123 Trento (TN), Italy
The acoustic emission technique is an effective way to acquire crack information from material bodies at the microscopic level. Monitoring of the acoustic emission events provides a deeper understanding regarding the structural health status of critical constructions such as bridges, railways, pipelines, pressure vessels, etc. Thanks to acoustic emission monitoring systems, it is possible to avoid catastrophic events and save lives, time, and money. For this reason, efforts to develop new acoustic emission sensor technologies, as well as the use of current acoustic emission sensors in new research fields, will contribute to the limited literature sources.
Optical sensing systems provide good alternatives to the existing sensing technologies because of their wide range of detection bandwidths, adaptation to harsh environments, and low sensitivity to electromagnetic interference. For this reason, in this talk, two sensing approaches that enable the detection of acoustic emissions by optics will be presented.
The first sensing approach consists of thin-film optical filters and an elastic microcavity layer. The sensing mechanism is similar to the Fabry Perot structures and it relies on resonance shifts of the cavity when there is a change in the cavity thickness similar to the Fabry Perot structures. Thus, the design, fabrication, and demonstration steps of a Fabry Perot elastic microcavity have been presented. Throughout the fabrication efforts, a new deposition protocol was developed. This deposition technique has enabled the deposition of thin-film optical filters on flexible substrates via the RF-sputtering technique. Therefore, a new sensing approach has been developed. In the second approach, an easily implementable optomechanical device for pressure and vibration sensing using a multilayer structure on a flexible substrate will be demonstrated. The design, fabrication, and evaluation steps for a proof-of-concept sensor as well as optical glass components. The design steps include optical, mechanical, and optomechanical correlation simulations using the transfer matrix method, finite element analysis, geometric optics, and analytical calculations will be presented.